Thank goodness human growth rates don't match that of trees. For if it
did then we would tip the scales of well over a ton by the time we reach
retirement! Consider this new research from the Smithsonian Tropical Research
Institute (STRI) recently published in the journal Nature. According to
the new study, trees put on weight faster and faster as they grow older. Because
most trees' growth accelerates as they age this suggests that large, old trees
may play an unexpectedly dynamic role in removing carbon from the atmosphere.

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Richard Condit, staff scientist at the STRI, devised the analysis to
interpret measurements from more than 600,000 trees belonging to 403 species (from
both tropical and temperate climates). "Rather than slowing down or
ceasing growth and carbon uptake, as we previously assumed, most of the oldest
trees in forests around the world actually grow faster, taking up more
carbon," Condit said. "A large tree may put on weight equivalent to
an entire small tree in a year."

"If
human growth would accelerate at the same rate, we would weigh half a ton by
middle age and well over a ton at retirement," said Nate Stephenson, lead
author and forest ecologist with the U.S. Geological Survey.

The
ramifications of this study are huge because it highlights the importance of
protecting the largest trees even more aggressively to take advantage of its
carbon uptake in and effort to impact climate change. We have long appreciated
the importance of the large tree for its habitat but this study demonstrates
that a large tree can add as much carbon in one year as an entire mid-sized
tree will do in its lifetime. Yet the large tree is often the first to be
harvested and is also more prone to variations in climate conditions.

But with this study in hand, researchers anticipate that forest
conservation and reforestation may mitigate global warming by reducing carbon
dioxide in the atmosphere. Therefore they will track the growth acceleration of
individual trees to determine if their growth does translate into greater
carbon storage as forests age.